added a static method to check whether a certain value is allowed in an access path
added a static method to check whether a certain value is allowed in an access path

kaunder/soot-infoflow,secure-software-engineering/soot-infoflow,wsnavely/soot-infoflow-android,xph906/FlowDroidInfoflowNew,matedealer/soot-infoflow,lilicoding/soot-infoflow,wangxiayang/soot-infoflow,jgarci40/soot-infoflow,johspaeth/soot-infoflow